Be aware that there is no anti-aliasing filter in the AudioMoth so you need to select a sample rate at least twice the maximum frequency in the environment - not just the maximum frequency of your target signal.

I cut through the hot-melt glue with a scalpel - but be sure to cut between the glue and the battery holder to avoid the possibility of damage to the circuit board. When soldering/desoldering the battery holder terminals take great care not to bridge between the terminal pads and the adjacent via holes (they are very close). I inadvertently did this on one of my original AudioMoths (-ve terminal) since when it will not accept power from the USB. (Fortunately this does not affect operation on battery power).

Brome The MH-C9000 carries out an impedance check on each cell before charging - if the cell fails this it is rejected and the charger displays "HIGH". This is one indication of a failing cell but more basic chargers would carry out a charging cycle regardless. Sometimes cells are incorrectly rejected as high impedance so it can be worth completely discharging and trying again. If a cell passes this test then you can carry out a "refresh and analyze" cycle in which the cell is fully charged and then discharged, measuring and displaying the total remaining capacit, so you can sort your batteries into matching sets. I write the measured capacity on a strip of white adhesive tape and use only the "best" cells in my bat detectors. The charger also has a "break-in" mode that can sometimes restore the capacity of a cell that has been lying about for some time - however it is a very long process since the cells are trickle-charged for 16hours to force a full charge (the entire cycle (charge - discharge - re-charge) can be up to 48 hours - assuming the cells have first been fully discharged!)

Check out the battery health with a good quality charger/analyzer before important deployments. I use a Powerex MH-C9000PRO, which will charge/analyze four AA and AAA cells. It will identify failing cells and has a charge/discharge cycle mode that reports the capacity of each cell. https://mahaenergy.com/battery-charger-analyzer/

The hot-melt glue does have a tendency to let go but not as often as you are experiencing - and particularly with a brand-new device! It's possible that there could be some contamination on the PCB so try degreasing with a drop of alcohol on a cotton bud before replacing the glue. Also avoid applying pressure to the board whilst the glue is setting otherwise you may twist the board and apply additional stress to the glue joint. The glue joint will always be a weakness so be sure to hold only the battery clip whilst removing and replacing batteries and hold the circuit board only when removing and replacing the memory card and manipulating the mode switch.

@Alex Rogers Thinks for continuing to try - unfortunately this version of the app still will not work. I'm beginning to think that the problem may be the Fire OS - it's only BASED on Android 9.0 so something important may have been crippled by Amazon.

Hi Alex, Thanks for trying! As you predicted I can now adjust the volume setting but unfortunately the AuidioMoths still will not recognize the tone.

I'm impressed with a reply within 10 minutes on a Saturday morning! I assumed there must be something different about the Amazon Fire. However, as a test, I have just installed a random tuner/metronome app on the tablet and the output level from this app IS properly controlled by the main volume control (ie media output level). This suggests that there is an issue with the AudioMoth App that makes it look like an alarm app to the Fire tablet. Obviously this is not a problem on most 'phones or tablets - otherwise you would have been inundated with complaints that the app doesn't work!

@Alex Rogers I've attached recordings of chimes at lower volumes, to avoid clipping. I'm still seeing the same effect - the app chime is not decoded whereas the website chime is accepted by the AudioMoth, both as played from the tablet and also when the recording is played back from my PC. There is another issue with the AudioMoth app that makes setting the volume difficult. The volume of content played from the web browser is controlled by the Media Volume whereas the sound from the app is treated as an alarm. The Fire HD volume control affects only the Media Volume so the app sound level can only be adjusted from the advanced settings menu.

@Edgars Dzenis Whilst AudioMoths are currently unavailable, an alternative would be the HydoMoth. Alex Rogers has recently confirmed that the HydroMoth is functionally identical to the AudioMoth (apart from the absence of GPIO or external mic pads). The HydroMoth also has an additional Low Gain mode and an optional Delayed Start facility that allows you to enable the custom mode without opening the case, using a magnetic reed relay - could be useful on land if you are deploying the device in wet weather. There is currently an active campaign on GroupGets scheduled to end on 21st August. The HydroMoth is somewhat more expensive than the terrestrial AudioMoth because it comes together with an underwater case. You would have to replace this with a standard case with an acoustic vent - or possibly drill out the mic aperture in the hydro case and fit a weatherproof acoustic membrane. David https://www.openacousticdevices.info/support/device-support/hydromoth-as-normal-audiomoth https://github.com/OpenAcousticDevices/Application-Notes/blob/master/Using_HydroMoth_to_Make_Underwater_Recordings/Using_HydroMoth_to_Make_Underwater_Recordings.pdf https://groupgets.com/campaigns/1061-hydromoth-round-2

@j.j.lloyd Jim, Apologies! I misread your original post and thought you were using Audacity. I also use Audition most of the time (although still using ver 3). It looks like you have sorted re-sampling in Audition, but, for anyone else who may be struggling, you need to use "Convert Sample Type..." (F11) rather than "Adjust Sample Rate" - on the Edit menu.

@j.j.lloyd Hi Jim, It is straightforward to resample a recording using Audacity - and an anti-aliasing filter is automatically applied before down-sampling. The procedure is a bit counter-intuitive, though, and you control the sample rate of an exported file by setting the "Project Rate" at the bottom left of the Audacity window. The "Rate" option on the track drop-down just changes the playback rate without resampling the data - so it changes the pitch and speed, as you have observed. Whilst the "Resample" option on the Tracks menu does what it says, it only resamples the selected track within Audacity and is used when you are mixing tracks recorded with different sample rates. Whatever the sample rate of an individual track within the program, it will always be resampled if necessary and exported with the selected Project Rate. Hope that may be helpful. David

@Alex Rogers I've attached recordings of the AudioMoth App and Website Chimes recorded on an AudioMoth, as instructed. Both chimes were played from the Fire HD tablet. When these recordings are played back via my PC speakers the Web chime sets the time on an AudioMoth but the App chime will not. David

@Alex Rogers My phone is still Android 2.3.6 so there is no hope at all that will work! The Tablet is an Amazon Fire HD 8 gen 10. It's running Fire OS 7.3.2.3 which is based on Android 9.0. In most cases Android apps work fine on this platform but overall it's a nasty piece of work and designed primarily to lock users into Amazon and boost Bezos' profits so it's possible there may be a compatibility issue. The idea of a downloaded web app sounds promising but I'm not sure whether the Fire/Silk Browser will support PWAs.

@Alex Rogers Thanks for your replies. It appears that the problem is with the AudioMoth app downloaded from Google Play. Your alternative firmware makes no difference - the app will still not set the time. However the chime from the webpage works perfectly when played from the internal speaker of the same tablet at about the same volume as the app (works even with firmware 1.6.0). Not a viable solution in the field though as it will depend on finding a wi-fi hotspot! The tablet doesn't have cellphone capability and my phone is too old to play the tones from the webpage (I can open the page but the tones won't play).

Kaleidoscope 5.3.9 also works - however I don't think that there is much difference between 5.3.8 and 5.3.9

@AdrienGelle Rather than mucking about with Python or R you can easily batch-add the serial numbers to the filenames using "Advanced Renamer" (free from www.advancedrenamer.com). The serial number is saved in the "Artist" tag prefixed with "AudioMoth " So to add this use the "Add method"... Add: _ At index: 0 Alternatively, Advanced Renamer can read text directly from the file - so to add the serial number without the prefix you can use... Add: _ At index: 0

The recorded level will, of course, depend upon the incoming signal level. The AudioMoth uses two cascaded op amps and from the settings in the fimware the gain in the various settings is as follows: OPA1 OPA2 Total Normalized 0 Min ×4.33 ×1 ×4.33 ×1.00 1 ×7 ×1 ×7 ×1.62 2 Med ×15 ×1 ×15 ×3.46 3 ×15 ×1.67 ×25.1 ×5.80 4 Max ×15 ×2 ×30 ×6.93

I'm surprised that you haven't had a response from the AM team! Parts data is available on circuithub at https://circuithub.com/projects/OpenAcoustics/AudioMoth According to this info the mic is a Knowles SPM0408LE5H-TB

Pooja Before we speculate about the cause of this effect please post an original wav file of one of these recordings (ie EXACTLY as saved by the AudioMoth).